Determination of optimal parameters for rapid prototyping of the involute gears

Nowadays, rapid prototyping technologies are available at very affordable prices. This is the main reason why they are being used in almost all industry sectors. 3D printers are currently being widely used for rapid prototyping and development of the new products. However, taking into account the permanent progress of rapid prototyping materials mechanical characteristics (usually different kinds of plastics), 3D printers are sometimes used even for production of the failed parts replacements - operating at the low load and rotational speed conditions. This is the main goal of this paper - to establish optimal 3D printing parameters (printing direction, layer height and percent of infill) which will allow printed gears to replace failed steel gears, for at least some time, enough for spare steel gears to be produced and delivered on site. Taking into account previously mentioned facts, the application of the 3D printed gears can potentially provide the reduction of maintenance delays in different industrial facilities (factories, workshops, etc.) which will consequently lead to significant energy and financial savings

DETERMINATION OF CRITICAL SIZE OF CORROSION PIT ON MECHANICAL ELEMENTS IN HYDRO POWER PLANTS

Researchers in the field of fracture mechanics, predominantly developing appropriate solution algorithms for problems of solid bodies with cracks. Problems in mechanics generally, related with fracture and fatigue for solid bodies with various geometries of sharp notches, are studied to a much lesser extent. This situation can be explained by analytical difficulties arising in solving problems of elasticity theory for bodies with rounded notches. To solve problems of such class, starting from data on stress concentration in the rounded notch tip with a significant radius of curvature, simplified solutions with are therefore of great importance. Recent years, due to constant rise of computing power and development of numerical methods, re-evaluation of stress concentration factors from a viewpoint of theory of elasticity is present. This is mainly as a feedback from industry, which have requirements toward mega and nanostructures. Corrosion represents an important limitation to the safe and reliable use of many alloys in various industries. Pitting corrosion is a form of serious damage on metals surface such as high-strength aluminum alloys and stainless steel, which are susceptible to pitting when exposed to a corrosive attack in aggressive environments. This is particularly valid for dynamic loaded structures. The basic idea behind this paper is finding links between different scientific and engineering disciplines, which will enable useful level of applicability of existing knowledge. The subject of this paper is application of new method of determine length scale parameter for estimating the mechanistic aspect of corrosion pit under uniaxial/multiaxial high-cycle fatigue loadin

Dynamic properties modeling analysis of the rubber-metal elements for electric drive

The gradual increase in the volume of electric vehicles leads engineers to solve completely new problems of NVH (noise, vibration and harshness) One of the solutions is the use of rubber mounts to hold the electric motor of the vehicle's powertrain. This article deals with a rubber mount used to insulate vibrations from the propulsion system to the rest of the vehicle. Since the electric motor produces a different spectrum of vibrations and noise than the internal combustion engine (it produces lower amplitudes, but in a wider frequency band), it is necessary to adapt the design of the rubber mounts. This article deals with the possibility of using a mathematical model that can be used in a virtual vehicle model. It compares the differences in the vibrations of the internal combustion engine and the electric motor. From the results measured on the experimental model, the parameters for the FEM model and the mathematical model were identified. At the end of the article, the results from the experiment are compared with the results from the simulations

Dynamic properties modeling analysis of the rubber-metal elements for electric drive

The gradual increase in the volume of electric vehicles leads engineers to solve completely new problems of NVH (noise, vibration and harshness) One of the solutions is the use of rubber mounts to hold the electric motor of the vehicle's powertrain. This article deals with a rubber mount used to insulate vibrations from the propulsion system to the rest of the vehicle. Since the electric motor produces a different spectrum of vibrations and noise than the internal combustion engine (it produces lower amplitudes, but in a wider frequency band), it is necessary to adapt the design of the rubber mounts. This article deals with the possibility of using a mathematical model that can be used in a virtual vehicle model. It compares the differences in the vibrations of the internal combustion engine and the electric motor. From the results measured on the experimental model, the parameters for the FEM model and the mathematical model were identified. At the end of the article, the results from the experiment are compared with the results from the simulations

Determination of optimal parameters for rapid prototyping of the involute gears

Nowadays, rapid prototyping technologies are available at very affordable prices. This is the main reason why they are being used in almost all industry sectors. 3D printers are currently being widely used for rapid prototyping and development of the new products. However, taking into account the permanent progress of rapid prototyping materials mechanical characteristics (usually different kinds of plastics), 3D printers are sometimes used even for production of the failed parts replacements - operating at the low load and rotational speed conditions. This is the main goal of this paper - to establish optimal 3D printing parameters (printing direction, layer height and percent of infill) which will allow printed gears to replace failed steel gears, for at least some time, enough for spare steel gears to be produced and delivered on site. Taking into account previously mentioned facts, the application of the 3D printed gears can potentially provide the reduction of maintenance delays in different industrial facilities (factories, workshops, etc.) which will consequently lead to significant energy and financial savings

Crossed helical gears with wheels from sintered steel with pyrohydrolysis

Crossed helical gears are used in cars and in many household appliances. The trend towards increased comfort in motor vehicles has led to the utilization of more than a hundred servo-drives in luxury class automobiles. Important advantages of the crossed helical gears are their easy and inexpensive design, good noise performance and high ratio that can be realized in one step. Sintered steel shows as very favorable material for wheels in crossed helical gears. High demands are set on gears made from sintered steel regarding wear, fretting, tooth fracture and pitting load capacity. This report shows results of iron-based sintered material Fe1.5Cr0.2Mo with pyrohydrolysis as additional treatment, in case of crossed helical gears concerning wear resistance and other damage types under different speed and load

Evaluation and choice of conceptual solutions for a universal geared engine reducer

This paper deals with the issues of evaluation and choice of conceptual solution for a universal motor gear reducer, usually carried out during its development. It is a known fact that reducers could be delivered with a motor installed or in the so-called motorless version. In case of the delivery version with the motor, they could be equipped either with special reducer electric motors or with standard (IEC) motors. In case of a reducer intended for the special motor, in motorless version it has to be equipped with IEC motor adapter, for the customer’s option to use standard motors, plus it should have a classic input shaft. In case of a reducer delivered with IEC motor, its motor might be connected indirectly, using IEC motor adaptor, or directly onto the reducer, without the use of adaptor. In both cases the reducer has to be delivered with a classic input shaft. This paper conducts the evaluation of some particular solutions by leading reducer manufacturers, with the intention to point out the most satisfactory conceptual solution

The influence of corrosion on stress concentration factor at shaft to flange radius

This paper describes the influence of corrosion on stress concentration factor and crack initiation at shaft-flange transition section. The real turbine shaft failure case study is used for research. This case study and numerical calculations show that the seal box solution led to constant leakage of river water in the zone of critical radius and resulted in corrosion fatigue cracks and turbine shaft failure. Thus, the Finite Element Analysis is performed to calculate the stress concentration factor increase as a result of corrosion occurrence. The corrosion at shaft-flange transition section is modelled in the zone with maximum stresses with a corrosion pit dimensioned to comply with real in situ dimension of pits. The presented research points new trends in stress concentration factor calculation. The obtained numerical results for maximum stress and stress concentration factor in critical zone confirmed failure analysis study outcome